Risks of long-term vision loss after trabeculectomy identified

Risk factors for long-term vision loss after trabeculectomy included preoperative split fixation on visual fields, according to a study published in the Archives of Ophthalmology.

The study led by Dr Brian A. Francis, Department of Ophthalmology, Doheny Eye Institute, Los Angeles, California, USA, investigated the medical records of 301 eyes in 262 patients who underwent trabeculectomy between January 1999 and September 2003. Mild or moderate postoperative vision loss was categorized by a decrease in Snellen acuity of 3 – 5 lines. Permanent postoperative vision loss was identified if visual acuity did not return to 3 lines within the 6-month follow up period.

Of the 301 eyes studied, 24 suffered from permanent vision loss, 13 presented with mild or moderate vision loss and 11 experienced severe vision loss. Permanent mild or moderate vision loss in 10 eyes and permanent severe vision loss 6 eyes had no identifiable cause.

Transient vision loss was experienced in 170 eyes. This consisted of 79 eyes with mild or moderate vision loss and 91 eyes with severe vision loss. The mean recovery times were 88 days and 78 days, respectively.

The risk factors identified in the study included preoperative split fixation on visual fields, preoperative number of quadrants with split fixation, and postoperative choroidal effusions with eventual resolution.